In the world of tropical reef fish, there are numerous examples of convergent evolution, where unrelated and widely separated fish develop the same color and shape. The similarity between some cases of convergent evolution can be so similar between these fishes.
Starcki damselfish and resplendent angelfish are both blue, oval-shaped fish with a yellow back. Narcosis angelfish and the yellow teardrop butterflyfish are both flat yellow fish with a big black spot on the side of their upper body.
These fish are not only not closely related, but they live great distances apart, sometimes in different oceans! But the best case of convergent evolution, especially in common aquarium fish is the royal gramma and the royal dottyback.
The royal gramma, Gramma loreto, is a small species of basslet from the tropical west atlantic which grows to about two inches and is bright purple in the front and yellow in the back. The royal dottyback, Pictichromis paccagnellae, is a small species of pseudochromis dottyback from the Indo-Pacific ocean which grows to about two inches and is bright purple in the front and bright yellow in the back.
Despite these superficial similarities, royal grammas and royal dottybacks are quite different in appearance. Differences in overall body shape, eyes, fins and precise color pattern make it easy to separate one species from the other. This is where the light hearted graphic of Comicquarium can really help educate new saltwater fish keepers about the differences between the two species.
They may look somewhat the same but it’s important for aquarists to know the difference between a peaceful royal gramma and a pugnacious royal dottyback. Better yet, what we especially love about this graphic is that it takes a special eye for fish to spot all the nuances between these very similar looking fish, and it can train you to see subtle differences in other less common species of reef fish.